It’s a phrase that’s bandied around to scare fat people into feeling as if their condition is contagious, and perhaps they should be put into quarantine where no perfect thin people can see them until they are thin enough for society to handle.

But what’s caused it?

The government and most slimming companies say it’s fat. Low carb afficionados say it’s sugar. Some people think it’s all because we’re living in a junk food filled obesogenic environment where high calorie food is cheap and exercise optional. Daily Mail commentators believe it’s because we’re all lazy, greedy and worthless.

I’ve long believed that it’s none of the above. OK, if we’re going to be honest, yes people are fat because they eat too much. That’s bleedin’ obvious. But why? Why are people eating and overeating to the extent that they are affecting their health, whether it’s their physical health or their emotional well being that’s at risk?

There’s no doubt that things have got worse over the last 20-30 years. At the same time, the message that we have to be thin has increased in volume and is assaulting us from all angles. I grew up in the 80s when there was only one magazine devoted to dieting in the UK, Slimming magazine. There were no celebrity trash rags like Closer, Now or Heat, splashing fat/thin/pregnant/over-botoxed celebrities on the cover and pulling their appearances to pieces for entertainment. There was no Internet. No mobile phones for selfies, no Twitter or Facebook.

There were no faux-concerned MPs making a big deal about reducing the number of fat people (why not just shoot them?)

You could argue that 25 years ago, there was no need for any of the above because there weren’t so many fat people. But look at it this way. Everywhere we go, we’re bombarded with the idea that we’re fat. Or if we’re not fat already, if we’re not careful, we could end up fat. we’ve all grown up thinking that being or even eating fat is a BAD thing. And this obsession with weight, wrapped up in pretend concern for our health, is so ingrained in our psyches that we find it really hard to ignore it. Of course, some people ignore it. These lucky people are the ones who have a normal relationship with food and rarely give their weight a thought.

Most of us fight an ongoing battle with food, even if we don’t think we do. If you worry that you’re going to get fat if you eat whatever you like, deny yourself certain foods to avoid putting on weight (but secretly crave them), think of certain foods as off-limits because you know you won’t be able to stop eating them once you open that packet…you’re caught up in it too. Even if you aren’t fat.

Have you ever wondered why the first thing you do when you plan a diet is stuff your face for the entire weekend before you start?(nobody ever starts a diet on a Wednesday afternoon, do they) It’s how your brain is wired. It’s not just a case of wanting what you can’t have – it’s a throwback to when we lived in caves. I’m not talking about the Paleo diet either. We have two sides to our brain, the conscious and sub-conscious, and the sub-conscious is automatic. It does things for us without us asking it to, like making us breathe, making us feel thirsty when we need a drink, making us feel hungry. Although eating, breathing and drinking are all under our physical control, we get very strong signals to do all three when we need to, and if you’ve ever tried not breathing, you’ll realise that you physically can’t do it for too long before your brain takes over and makes you take that breath whether you like it or not.

It’s the same with food. Your subconscious brain picks up on very subtle cues, and all it wants to do is look out for you, so when it gets wind of the fact that you’re having a fat day and thinking of going on another diet, it starts you thinking about food. It thinks there’s a famine coming. It knows that when you have that feeling, it ends up hungry, so it does everything it can to make you think of food constantly until you give in. It’s out of your control, even if it’s irrational. It’s the same kind of irrational reaction that makes you jump when someone leaps out on you in the dark, or freak out over a harmless two inch house spider. The threat of an oncoming diet spurs your protective mechanisms into making you think of food…all the time.

So how does that make people fat?

To put it in simple terms, just thinking you’re too fat and have to go on a diet will make your subconscious bully you into eating things you don’t let yourself eat when you’re on a diet. Some people can use enormous amounts of willpower to resist the subconscious’ nagging. Some people manage it for a very long time and do lose weight. But 95% of them will put it back on as soon as they give up that control, and many end up back where they were or even bigger.

And everywhere, all over the place, are people, magazines, TV shows, websites and more telling us we’re too fat.

We’re constantly scaring our subconscious into making us obsess about food!

How do we stop it, though? That, my darlings, is the tricky bit.

(All this is also explained in much better detail along with some really good ways to switch off the automatic reaction, stop the overeating before it starts, and get a normal relationship with food again in ‘Eat less without trying to eat less‘ by Sue Thomason.)